fluttering or compressor surge?

[Migillicuty420a]

According to Wikipedia Surge is the rate of change of acceleration in physics. The air in the intake got stopped dead in its tracks when the throttle plate closed and now has to equalize as fast as possible. The only way out is the way it came in...the turbo. Air going the opposite direction on those compressor blades is going to try and make the turbo spin the exact opposite way it did to compress the air. This is why some turbo shafts get bent. Flutter and surge are the same thing. BAD

[MrShakotan]

@Migillicuty420a no no no no no. this is flutter, compressor surge is completely different. Who ever started saying that this will kill turbos should get a kick in the pants.

[Migillicuty420a]

@MrShakotan So is flutter just when the blow off valve opens and shuts really quick? My friends dad owns High Tech Turbo Co and I have personally seen in their shop what any air going back out on the turbo can do to the inconel shaft.

[MrShakotan]

@Migillicuty420a flutter normally happens when the BOV doesnt open at all or there isnt one. My car will flutter sometimes if i let off the throttle as its building boost as these only a couple of psi at most and its not enough to open the BOV. My complete turbo system is basically stock except the FMIC, BOV is stock. Search 'real compressor surge' there is a red r33 on a dyno that is showing what compressor surge actually is.

[liledd8728]

that is compressor surge. Your blow off valve is not opening up early enough to let the pressure built by the turbo out. just adjust your blow off valve and everything will be fine.

[tehbabyjebus]

Also so far what I have asessed from what I have read.. is that my HKS SSQV is not supposed to do this at all? It is supposed to have a clean release at all boost levels? and the adjustment nut does nothing to help.. I just don't want to have to replace an expensive ass turbo.. thanks to any help.. (video is my only upload)

[tehbabyjebus]

Instead of reading pages of comments.. if anyone wants to look at my only video upload and let me know if I am compressor surging or just fluttering please do and inbox me/ reply2comment.. Im getting paranoid because I don't have the money to replace a turbo.. Mine only flutters when I let off the throttle, not during boost.. So I am assuming it is safe.. but I have also heard stories about new bovs or rerouting vaccum lines solving flutter.. help?

[manthony65676567]

did you crank the engine a couple of time before turning it on?

[cruiserboy1000]

Holy shit there are alot of idiots on here!!! this is turbo FLUTTER, where the compressed air has no where to go when the throttle butterfly shuts and the compressed air has to run backwards through the turbo and the fluttery sound is made by the compresser whell 'chopping' the air. True compresser surge is where the turbo is under pressure/load and the engine can not take the amount of air being forced into the intake and has to run back through the turbo at high RPM, very bad.

[bonecrime]

@cruiserboy1000 So? It's the same process, with either a closed or open throttle. I'd guess neither is very good for the turbo...

[AbstractReaIity]

the fluttering sound IS surge, positive pressure slowing down or stalling the intake wheel. that guy with the 20 thumbs up is full of shit, you need a to vent this pressure regardless.

like metalseanhead said.

[Clesarie]

Thats flutter for sure. Creping more like what HKS sound like. Like a bird stuck in our engine sound :P

[DKSLIDER86]

Thats a flutter

[killacamry24]

Flutter is harmless unless your over 1 bar.

[bonecrime]

@killacamry24 When you close the throttle, wont the pressure build up over 1bar in the intercooler and pipes when the air has nowhere to go?

[adamski100988]

thats flutter not surge,,,just the choppy sound of the air passing through the comp blades!!

[munnsey]

Search ... Audi Quattro Sport S1 Rally Group B "Total Tribute"

A great video with some amazing flutter noises!

[munnsey]

Group B rally Audi Quattros from the 80's...Search vids of these on here and you will hear huge flutter noises, Big turbo,big Boost pressures, No BOV was ever used and they never suffered from sudden failures.

[csd19]

@munnsey That'll be the external wastegates they used....

[csd19]

@csd19 And I'm talking about the Audi Group B rally cars btw. massive external wastegates to go with the big turbos.

FFS even the factory Audi Quattro turbo road cars came with external wastegates...

[munnsey]

No BOV fitted,Most turbo cars will make the flutter sound if the airbox is removed and no air filter or just a large cone air filter. These days OEM spec cars will have a recirculating BOV to help cancel any flutter noise and airbox design also plays a big part at silencing any turbo noises.Many older turbo cars (1980's) did not even have BOV's fitted, just the airbox on its own does a good job at silencing odd noises.

[one8apc1]

Flutter. Just tighten the BOV.

[devinsorter54321]

bov flutter

[bpunlife]

ok so i had a buddy with a turbo supra t78 single turbo andhis car did it, he had two HKS BOV's. I doubt it is the BOV being insufficient seeing as he had two. My buddies STI does it, My buddies evo9 does it, and my sr20det does it. all with different BOV. we all have boost gauges and no signs of surging. sounds like the wastegate fluttering. do you have exhaust that usually makes it more noticeable.

[roflex2]

@bpunlife Simply a moron without a clue. Wrong wrong and wrong.

[bpunlife]

@roflex2 its not compressor surge. compressor surge is under throttle. its just a mixture of the wastegate and air going through the intake. what car do you drive? i have an sr20det with a gt2871 with the anti surge housing. i also have 740cc injectors a 38mm external wastegate. walbro fuel pump. z32 maf. blitz intake. greddy type s bov, 3inch turbo back exhaust. greddy front mount intercooler. hks evc ez2 boost controller. and i am sure i am missing a few things. i made 389.8hp to the wheels

[tevinm14]

im thinking thats a flutterdump my friend

[bendrives6]

that sounds more like the intake my volvo 850 does that

[crzygutrsnobrdr]

flutter..listen to supras with t-88's thats compressure surge

[454sskilla]

flutter!

[metalseanhead]

You guys are idiots, surge sounds cool but it can actually kill your turbo.

IF you don't sort it out though it will split your compressor wheel nut off, which destroys the thrust bearings and bends the compressor blades backwards.

SO you guys are dicks for not sorting out compressor surge when it occurs. you don't deserve a car if you want to destroy it cause it sounds cool to do so.

[crayman31]

What an exaggeration - if this was the case, every high HP turbo drag car would be blown to smithereens.

It does put more stress on the thrust bearing but it doesn't turn your turbo in a death star - just may shorten it's life a little.

[blyndrotor]

Same comment different videos.

This man is on a mission.

[oilfield666]

not only that you can sheer the shaft in half sending the left overs of the turbine into your intercooler

[roflex2]

@metalseanhead Bends the compressor blades backwards ahaha are you serious? If it could do that then surely when you close the throttle it would just bend the throttle plate?

Compressor surge or flutter on throttle off is fine as there is no longer any torque being applied to the exhaust wheel. Compressor surge when on throttle however is bad and does kill turbo bearings.

[JLDG4]

@roflex2 Finally someone puts these dumb asses in their place!...im sick of people commenting on these "flutter" vids saying " oh thats compressor surge!"...they dont know shit!.....and if they still think they do, then show me ONE turbo that has been destroyed by this

[roflex2]

@JLDG4 Yeah they don't know the differnce between flutter when you throttle off and flutter when you are on throttle, the later kills things, the former is harmless.

people go listen to all the turbo F1 and rally cars, if they wanted their turbos to last longer (they do) then they would fit a bov, but the reality is you get better throttle response without one and it is only for sound and emissions that they are fitted,.

[PearyHD]

@roflex2 mm..with bov u get better throttle response..-.-

[roflex2]

@PearyHD Actually you don't you get better throttle response with a bov, all rally cars DONT run them for this reason. Running no BOV leaves compressed air in the intake tract for instant air on gearchange, also on partially throttle the bov doesn't release all the air. Seriously I've tried it, the difference is massive, all this talk of better throttle response with a bov is spin bullshit from the BOV manafacturers.

[PearyHD]

@roflex2 well i dont know how much the potential air hitting the compressor wheel will slow it down(what i've learned is that when u close the throttle the air will go back to the compressor wheel and if you don't have a bov its gonna slow it down?), atleast to me its somewhat obvious that if the compressor wheel is slowed down by the air it takes more time to get it to fully spool up? resulting in a better throttle response..how much boost are rally cars runnin' anyway?

[roflex2]

@PearyHD Yeah but you lose a massive amount of compressed air out the intake and that takes even longer to replace than for it to get back up to speed.

[PearyHD]

@roflex2 well, since you're tried it and there was a difference then ok ;)

[atila007]

@metalseanhead thank you least someone knows a little something bout turbo's. the surge sound is caused by the effects of the intake system so instead of air constantly flowing back out of the turbo it comes out in bursts which is caused by pressure waves in the piping hitting the compressor. you dummy's need to realize that kind of pressure will blow your turbo and even your engine because the air flow from the turbo goes directly through your throttle body. too much pressure and boom.

[SyrusFox]

@metalseanhead Totally correct that awesome sound is compressed boost running back into the turbo and that flutter noise is that air hitting the blades which eventually bend then and poof ur fucked.. that oke who said flutter is completely harmless is a doosh

[badboihamza]

a closed circuit recirculating system, which circulates the pressure from the downstream side of the turbo and injects it back in before the turbo impellor. These systems actually keep the turbo's spinning much faster than normal BOV's. therefore less lag if youre running a bigger turbo and better life expectancy of your turbo. but no cool blowoff valve sound.

[blyndrotor]

And a nice hot spike in your intake temps to boot.

Not really much to worry about so long as the engine is not to highly stressed.

Just making a point that many overlook.

Personally I prefer a hybrid setup to get a litle of the best of both worlds.

[juicyhung]

It was the first time I started the car so I had the radiator cap off to bleed off any air in the lines; since I also replaced the coolant.

[PestVic]

:40 were you running it with no radiator cap?

[07CSMtc]

Definitely flutter considering that you aren't giving it enough rpm's to really build up boost.

[soccur04]

Wastegate flutter and compressor surge are completely different different. juicyhung and munnsey got it right.

[juicyhung]

After I replaced Flyin Miata's crappy BOV with a Mitsubishi 3000GT valve it no longer flutters.

[UltimateTuner10]

I have the GFB, I like it.

[wrx4life44]

@juicyhung yeah was gonna say has to be a crappy bov seems like its not opening under low boost thus causing air to go back the wrong way through the turbine

[munnsey]

thats fluttering you have there, completely harmless and you are only hearing it because of the big cone filter and presumably no BOV fitted. If you are running high boost 15psi or more then you should use a BOV, otherwise it wont matter. Compressor surge is actualy when you get a similar sound to flutter but it occurs during actual boosting, not after throttle release. Its when the turbo is pumping in more air then the engine can swallow.

[imickey503]

And today, I just learn something that was not in any book magazine or publication.. Thanks dude!

[atomgonuclear]

imickey503 your wrong, actually its when you let off the gas and the throttle body closes that way the air backs up in the intake and surges the compressor, it usually happens when you back off, not when your boosting

[crayman31]

Actually it happens when boosting - there's 2 types of compressor surge. One type is as you explain, the other is on boost where the turbo creates more air than the engine can ingest and air 'chirps' its way back through the compressor blades on boost. A too large turbo or inbalanced turbine/compressor wheel choice causes the 2nd type which I've experienced.

The 2nd type is detrimental to the turbo as it's during high load conditions this occurs!

[blyndrotor]

Nice to see someone who knows the difference between bad and minor surge.

[VentoDriver]

@crayman31 Now that I've read your comment I'm asking myself if I've got compressor surge problems...

I've got a stock turbo diesel, and when I'm flooring it, I feel the boost is not constant and I hear lots of "pshhht pshhht" coming from around the turbo, so I thought it was the waste-gate cutting of the boost because of cold air the pressure is getting too high.

Is my engine destroying itself or is it normal?!?!?!

[chickenhead2]

@VentoDriver it is probably your wastegate. do you have a boost gauge?

[VentoDriver]

@chickenhead2 nope, no boost gauge...but the summer is comming with warmer temp and it doesn't do it as often as it used to

[atomgonuclear]

I am ammending my statement, I have no been introduced to boosting compressor surge, nasty stuff, crayman is right too

[mediarocker543]

@munnsey, you're a jackass. Any compressor surge is bad for any boost rating. It stresses the compressor and makes it apt for failure. According to the OP, once he replaced his BOV, he had no more fluttering, which leads me to believe his BOV was inefficient (causing light surging, AKA Flutterdump) or his BOV was causing the harmless kind of flutter dump. The best way to see this is by watching your boost gauge. If your needle bounces you've got some surge. Otherwise its just the BOV fluttering.

[muskyurine]

@munnsey : Your a retard. Dont try and sound smart by posting these technical idiotic ass comments. Your my friend are B.S. Surge is when the boost that the turbo makes cant go anywhere else but back out the compressor wheel forcing the turbine in the opposite direction of its original rotation. Pretty much pushing the air out of the turbo itself (Either because of a late opening BOV or no openng of the BOV at all)

[munnsey]

@muskyurine...OK Mr. nice guy. Explain then how it can turn backwards when the turbine wheel is joined to the compressor wheel, and the turbine is always being turned by the exhaust gases. You are hearing air going back through the compreesor the wrong way wheel yes, hence the choppy air sound, but the compressor wheel wont turn the oppsite way to normal rotation.

[muskyurine]

@munnsey Never did iI state the compressor wheel and turbine wheel rotate by themselves (or were on separate shafts).... I said the turbine (meaning the whole shaft itself) I never stated it turns backwards either. I said its forcing it. Meaning its trying to push air through the blades the opposite way . It destroys your bearing whether it be journal or ball.

[smtbbo]

@munnsey of course not... if the engine can't take the amount of air produced by the turbos there would be a turbo spike. Fluttering is actually the wastegates opening and closing at high speeds to maintain the pressure from rising. Fluttering can happen when easing off the throttle, but if it sounds when the throttle bodies are closed that is stopping your turbine and that is bad. At this point there is no more pressure to open the wastegates so that option si discarded.

[munnsey]

@smtbbo Fluttering compressor type noises dont coming from a wastegate. A wastegate (internal or external) simply direct engine exhaust gases away from reaching the turbine wheel, to control the maximum speed of the turbine and prevent overboosting.

[smtbbo]

@munnsey agreed... but to "direct" or actually "divert" the exhaust gases, it DOES have a gate that opens and closes and that can get to be pretty audible specially when trying to maintain a boost setting due to its cycle speed

[DIRTMANIAC17]

@munnsey compressor surge and turbo flutter are the same they both occur when the throttle body closes to fast for the pressure in the turbo to go anywhere but back past the compressor fan learn about it before u comment

[munnsey]

@DIRTMANIAC17 Real compressor surge occurs during actual boosting when the turbo is boosting max and pumping too much air for the engines needs! You get a similar noise but it is far more damaging than flutter when you release the throttle

PLease learn more yourself, there is a video on here showing it.

[munnsey]

@DIRTMANIAC17 Watch the video called "True Compressor Surge"

[bonecrime]

@munnsey Eh what? Does it matter if the throttle is open or closed? Surge is still surge either way. If you're at full boost and high RPM and suddenly close the throttle, what do you think happens? Pressure is gonna spike way up because the air has no way to go, and the compressor stalls. If surge happens during WOT, I'd say your choice of turbo/wastegate/boost/etc is pretty fucked or your boost regulation isn't working. What happened to common sense?

[cruiserboy1000]

@munnsey Thank god someone else understands! on low boost, 12-15 PSI turbo 'flutter' is harmless, above that, damage may be caused, and plus, flutter is really only slowing down and already slowing down turbo, where as compressor surge is exactly as you mention, presurised air trying to punch back through a turbo whilst under boost!

[badassdesigns]

Flutter and compressor surge is the same thing;) and yes that is flutter/surge.